Turbine-driven centrifugal pump



Sept. 10, 1963 Filed Dec. 15, 1959 J. R. LANG ETAL TURBINE-DRIVEN CENTRIFUGAL PUMP 2 Sheets-Sheet 1 Sept. 10, 1963 J. R. LANG ETAL TURBINE-DRIVEN CENTRIFUGAL PUMP 2 Sheets-Sheet 2 Filed Dec. 15, 1959 United States Patent 3 103 176 TURBINE-DRIVEfll ClilNTRIFUGAL PUMP John Russell Lang and George Frederick Arkless, Glasgow, Scotland, assignors to G. & J. Weir Limited,

Glasgow, Scotland, a company of Great Britain and Northern Ireland Ifiled Dec. 15, 1959, Ser. No. 859,695 Claims priority, application Great Britain Dec. 16, 195$ 4 Claims. (Cl. 103-87) The primary object of the present invention is to obviate in a turbine-driven pump the necessity for pump or turbine glands, whereby to permit both the pump and the a rt me to run at a high rotational speed on a common s a t.

A further object is to provide a turbine-driven pump in which the bearings are lubricated either with the fluid being pumped, with the turbine-operating fluid, or with a separate fluid whose subsequent mixing with both the pumped fluid and turbine operating fluid will not be objectionable.

Yet a further object is to provide a turbine-driven pump in which it is not possible for either the pumped fluid or the turbine-operating fluid to escape to atmosphere, a feature of particular application to turbo-driven pumps for pumping or to be driven by fluids which are radio-active or otherwise noxious.

A turbine-driven centrifugal pump according to the invention comprises a turbine wheel, a pump impeller, and a driving shaft common to both the turbine Wheel and to the pump impeller and rotatable in bearing means in a casing common to both the turbine and the pump, said bearing means being interposed between the pump impeller and the turbine wheel and being arranged to be lubricated with the fluid to be pumped, with the fluid for operating the turbine or with fluid admitted separately to the common casing.

Where it is desired to lubricate the bearings with the fluid to be pumped, means is provided for ensuring that the pressure of said fluid on the surface of the shaft adjacent to the pump impeller is greater than that of the turbine-operating fluid on the surface of the shaft adjacent to the turbine wheel. Thus, fluid being pumped will flow axially through the bearing means into the turbine and will lubricate the bearing means before being mixed with the turbine-operating fluid.

Alternatively, where it is desired to lubricate the hearing means with the turbine-operating fluid, means is provided for ensuring that the pressure of said fluid on the surface of the shaft adjacent to the turbine wheel is higher than that of the fluid being pumped by the pump. Thus, the turbine-operating fluid will flow axially through the bearing means into the pump and will lubricate, the bearing means before being mixed with the fluid being pumped.

It may be, however, that neither the fluid to be pumped nor the turbine-operating fluid is suitable for lubrication of the bearings. For example, both fluids may have insuflicient viscosity, may be at too high a temperature, or may be carrying abrasive particles.

In such a case, the bearing means consists of two spaced bearings for the common shaft, said bearings being located between the turbine Wheel and the pump impeller. A third fluid, suitable for mixing with both the turbineoperatiug fluid and the fluid to be pumped, suitable also for lubrication of the bearings and at a pressure higher than both the pressure of the turbine-operating fluid at the bearing adjacent to the turbine wheel and the pressure of the fluid being pumped at the bearing adjacent to the pump impeller, is introduced between the two bearings in such wise that the lubricating fluid is caused to divide, part flowing through and lubricating the bearing adjacent to the turbine wheel, before mixing with the turbine-operating fluid, and the remainder flowing through and lubricating the bearing adjacent to the pump impeller before mixing with the fluid being pumped.

Any of the above-described methods of lubrication will achieve our objects as neither turbine nor pump glands are necessary and both the pump impeller and the turbine wheel can rotate :at high speeds on a common shaft; the bearing means being lubricated either with the fluid being pumped, with the turbine-operating fluid, or with a fluid suitable for mixing with both the turbine-operating fluid and the fluid to be pumped. The combined pump and turbine casing may so enclose the turbine and the pump that neither the turbine-operating fluid nor the fluid being pumped can escape to atmosphere.

One embodiment of steam-driven pump according to the invention is illustrated in the accompanying drawing, represented by FIGS. 1 and 1A, which is an elevation in section along the axis of the pump.

Referring to the drawing, 1 denotes a turbine wheel operable by an aeriform medium, for example, by steam. 2 denotes a pump impeller. 3 denotes a driving shaft common both to the turbine wheel 1 and to the impeller 2 and rotatable in bearings 4, 5 spaced apart in a casing 6 common both to the turbine and to the pump. The bearings 4, 5 are interposed between the impeller 2 and the wheel 1 and may be of plastic, carbon or other material suitable for lubrication by water.

Theimpeller 2 is of the shrouded type and is provided with integral rings 7, 8 which run, respectively, in wear and neck rings 9, 10. A space 11 between the inner diameter of the wear rings 9 and the back of the impeller 2 communicates with the suction of the pump or with a tank from which the impeller 2 draws the feed water by way of a connection 12 in the casing 6. Thus, the space 11 will be approximately at the pressure of the suction of the pump.

The turbine is of the impulse type so that the pressure of steam in the turbine casing 13 will be effectively the pressure of the turbine exhaust.

The axial thrust of the turbine towards the pump will be taken by a water lubricated thrust ring 14 abutting on a collar 15 on the turbine wheel 1 and interposed between said wheel 1 and the associated bearing 4. If, under certain running conditions, the direction of axial thrust is reversed, the resultant thrust towards the turbine is taken by a thrust ring 16 abutting on a collar 17 on the pump impeller 2 and interposed between the impeller 2 and the associated bearing 5.

The pump casing 18, a bearing pedestal 19 for the turbine and the pump and the turbine casing 13 are united to form a leak-proof casing for the whole assembly.

If the temperature of the feed Water being pumped is too high to be suitable for lubrication of the bearings 4, 5, owing to the low viscosity of water at high temperatures, cool feed water is injected through a connection 20 into the space 21 between the two bearings 4, 5. This supply of cool water (hereinaflter referred to as G) lubricating water) is at a pressure higher than either the turbine exhaust pressure or the pump suction pressure, whichever be the higher.

The lubricating water divides, part flowing through the bearing 4 between the associated thrust ring 16 and collar 17 and mixes with the turbine exhaust steam by way of a chamber 22 and a hole 23. The water is prevented from impinging on the turbine wheel 1 by a baflle plate 24 and a labyrinth 25. The turbine exhaust connection 26 is arranged at the bottom of the turbine casing 13 to ensure rapid egress of water droplets from the turbine casing 13 into the exhaust line. It is to be understood that if the turbine exhaust steam is superheated, it will immediately evaporate part or the whole of the lubricating Water as it enters the turbine casing 13.

The remainder of the lubricating water flows through the bearing 5, between the associated thrust ring 16 and collar 17, and into the space 11 at the back of the impeller 2 where it joins feed water leaking from the discharge side of the pump through the impeller rings 7 and the associated neck rings 9 to the pump suction by way of the connection 12.

If the feed water being pumped be at a temperature suitable for lubricating the bearings 4, 5, the connections for lubricating water may be omitted. As in a turbo-feed pump the discharge pressure from the feed pump is invariably higher than the turbine exhaust pressure, the pressure in the space 111 between the back of the impeller and the associated wear rings 10 will rise until the same quantity of leakage water flows from said space 11, by way of (the bearings 4, 5, t the turbine exhaust casing 13 as leaks between the impeller rings 7 and the associated Wear rings Thus lubrication of the bearings '4, 5 can be achieved without introduction of separate lubricating water and moreover internal leakage within the pump casing 18 is reduced.

It is to be understood that the reference in the specification and in the claims to fluid being pumped is to be read as covering not only the main discharge of fluid from the pump but also leakage fluid discharged from the pump.

What is claimed is:

'1. A turbine driven roto-dynamic pump comprising a turbine wheel, a pump impeller, means for supplying a fluid to said pump impeller, means for supplying a driving fluid to said turbine wheel, a driving shaft common to both the turbine wheel and the pump impeller, a comanon casing for the turbine wheel, the pump impeller and the driving shaft, bearing means for said shaft in said casing, means for withdrawing a portion of the fluid from the discharge of one of said turbine wheel and said pump impeller, means for reducing the pressure on the withdrawn portion of the fluid, means :for returning a portion of the withdrawn fluid at the reduced pressure to the means for supplying fluid to the pump impeller, and means for passing another portion of the fluid, the pressure of which has been reduced, through said bearing means to lubricate said bearing means.

2. A turbine driven roto-dynarnic pump according to claim 1, in which the means for withdrawing a portion of the fluid, Withdraws fluid from the discharge of the pump impeller.

3. A turbine driven roto-dynamic pump according to claim 2, in which the bearing means for said shaft includes spaced bearings, one adjacent to the turbine wheel and the other adjacent to the pump impeller, and which includes means for causing the portion of the withdrawn fluid which is passed through the bearing means to pass through said bearings in seriatim.

4. A turbine driven roto-dynamic pump according to claim 1 including a thrust ring on the shaft for axial thrust of the turbine towards the pump impeller, a second thrust ring on the shaft for axial thrust of the pump towards the turbine wheel, said thrust rings being bearing surfaces, and means for effecting lubrication of the bearing surfaces of both thrust rings by said another portion of the withdrawn fluid.

References Cited in the file of this patent UNITED STATES PATENTS 782,271 Ray Feb. 14, 1905 1,123,364 Peterson Ian. 5, 1915 2,475,316 Garraway July 5, 1949 2,702,093 Sherrill Feb. 15, 1955 2,707,919 Holzwarth May 10, 1955 2,715,367 Kodet, et al Aug. 16, 1955 2,839,005 Means June 17, 1958 2,842,306 Buchi July 8, 1958 12,933,044 Williams Apr. 19, 1960 2,956,502 Glaser et al. Oct. 18, 1960 

1. A TURBINE DRIVEN ROTO-DYNAMIC PUMP COMPRISING A TURBINE WHEEL, A PUMP IMPELLER, MEANS FOR SUPPLYING A FLUID TO SAID PUMP IMPELLER, MEANS FOR SUPPLYING A DRIVING FLUID TO SAID TURBINE WHEEL, A DRIVING SHAFT COMMON TO BOTH THE TURBINE WHEEL AND THE PUMP IMPELLER, A COMMON CASING FOR THE TURBINE WHEEL, THE PUMP IMPELLER AND THE DRIVING SHAFT, BEARING MEANS FOR SAID SHAFT IN SAID CASING, MEANS FOR WITHDRAWING A PORTION OF THE FLUID FROM THE DISCHARGE OF ONE OF SAID TURBINE WHEEL AND SAID PUMP IMPELLER, MEANS FOR REDUCING THE PRESSURE ON THE WITHDRAWN PORTION OF THE FLUID, MEANS FOR RETURNING A PORTION OF THE WITHDRAWN FLUID AT THE REDUCED PRESSURE TO THE MEANS FOR SUPPLYING FLUID TO THE PUMP IMPELLER, AND MEANS FOR PASSING ANOTHER PORTION OF THE FLUID, THE PRESSURE OF WHICH HAS BEEN REDUCED, THROUGH SAID BEARING MEANS TO LUBRICATE SAID BEARING MEANS. 